An example for an apparatus of the kind in question here is a freeze-drying apparatus as described in EP-B1-391 208 (U.S. Pat. No. 5,129,162). A plurality of containers containing a product that is to be freeze-dried must be loaded onto supporting surfaces of the freeze-drying apparatus. Unloading is required after performing a freeze-drying process. Due to the extremely large number of containers that are loaded and unloaded during a batch, these processes are no longer performed manually. Typically, the containers are transported to and from the freeze-drying apparatus on conveyer belts. The containers are transferred from the conveyor belt to the supporting surfaces located in the chamber and back therefrom, after performing the freeze-drying process, by means of a sliding element.
The loading of the supporting surfaces of freeze-drying chambers or similar equipment must take place under extremely clean conditions since the containers or bottles containing the product to be freeze-dried are initially opened. Usually, a plug having a recess for the removal of the water vapor, lies on the opening of each of the containers. After performing the freeze-drying process, the containers are closed in the freeze-drying chamber by moving the supporting surfaces together and forcing the plug into the container. Even though the containers have already been closed, the unloading of the containers from the supporting surfaces, and the transfer of the containers to a capping device, occurs under clean room conditions. In this respect, freeze-drying facilities are equipped with insulators—if they are not located in clean rooms. An insulator, that is preferably formed by transparent wall sections, encloses those areas of the freeze-drying apparatus in which clean room conditions are supposed to be maintained. This also includes the container feed and removal means. Compared to the typical clean rooms, an insulator has the advantage that the required clean room volume is significantly smaller.
In freeze-drying apparatuses and installations of similar type, the drive systems for the moving parts are a problem. A spindle drive is used in the aforementioned freeze-drying apparatus. The use of toothed racks is also known. Drives of this type require a lot of space. Moreover, such structures include relatively narrow indentations or recesses, that require long sterilization periods. Since lubricants can also lead to contamination, drives of this type must be operated “dry”. The consequence is increased abrasion, which likewise causes contamination.